Operating System - Questions

I am new to this forum, but i am also glad to meet new freinds.
I was searching on google about operating system and i landed to go4expert to pradeep's info.
Well i need some help on below topics, hopefully someone will help me out.

Rather wide ranging questions there. Probably what you need to do is buy a book about operating systems and read it. Or have a look at Wikipedia as it's bound to have in-depth articles about all these.